Mechanism of Werner DNA helicase: POT1 and RPA stimulates WRN to unwind beyond gaps in the translocating strand

WRN belongs to the RecQ family of DNA helicases and it plays a role in recombination, replication, telomere maintenance and long-patch base excision repair. Here, we demonstrate that WRN efficiently unwinds DNA substrates containing a 1-nucleotide gap in the translocating DNA strand, but when the ga...

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Bibliographic Details
Published in:PloS one 2009-03, Vol.4 (3), p.e4673-e4673
Main Authors: Ahn, Byungchan, Lee, Jae Wan, Jung, Hana, Beck, Gad, Bohr, Vilhelm A
Format: Article
Language:English
Subjects:
Aging
Base excision repair
Biochemistry/ and Repair
Biomedical research
Cell Line
Deoxyribonucleic acid
DNA
DNA biosynthesis
DNA helicase
DNA polymerase
DNA repair
DNA Replication
E coli
Endonuclease
Escherichia coli
Escherichia coli Proteins
Exodeoxyribonucleases - genetics
Gene expression
Genetics and Genomics/Disease Models
Genetics and Genomics/Genetics of Disease
Gerontology
Humans
Laboratories
Life sciences
Nucleic Acid Conformation
Nucleotides
Proteins
Recombination
RecQ Helicases - genetics
RecQ protein
Replication
Replication Protein A - physiology
Senescence
Substrates
Telomerase
Telomere-binding protein
Telomere-Binding Proteins - physiology
Telomeres
TRF2 protein
Unwinding
Werner Syndrome Helicase
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Summary:WRN belongs to the RecQ family of DNA helicases and it plays a role in recombination, replication, telomere maintenance and long-patch base excision repair. Here, we demonstrate that WRN efficiently unwinds DNA substrates containing a 1-nucleotide gap in the translocating DNA strand, but when the gap size is increased to 3-nucleotides unwinding activity significantly declines. In contrast, E. coli UvrD (3'-->5' helicase), which recognizes nicks in DNA to initiate unwinding, does not unwind past a 1-nucleotide gap. This unique ability of WRN to bypass gaps supports its involvement in DNA replication and LP-BER where such gaps can be produced by glycosylases and the apurinic/apyrimidinic endonuclease 1 (APE1). Furthermore, we tested telomere repeat binding factor 2 (TRF2), both variants 1 and 2 of protector of telomeres 1 (POT1v1 and POT1v2) and RPA on telomeric DNA substrates containing much bigger gaps than 3-nucleotides in order to determine whether unwinding could be facilitated through WRN-protein interaction. Interestingly, POT1v1 and RPA are capable of stimulating WRN helicase on gapped DNA and 5'-overhang substrates, respectively.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0004673